1. Field of the Invention
The present invention relates to a method of making a mesh structure comprising providing a starting material which has substantially parallel lines of holes or depressions defining elongate, side-by-side main zones between the lines of holes or depressions and intermediate zones between the holes or depressions in each line, and drawing the starting material in a direction substantially parallel to the main zones to stretch the starting material out into a mesh structure having orientated main zones with the orientations therein extending generally parallel to the drawing direction.
2. Description of the Related Art
GB No. 2 073 090B discloses such a method, used for making uniaxially-orientated structures, and GB No. 2 035 191B discloses similar starting materials, being stretched in two directions at right angles to form biaxially-orientated structures. GB No. 2 073 090B and GB No. 2 035 191B can also be referred to for background details on stretching and orientating plastics materials.
In the uniaxially-stretched materials of GB No. 2 073 090B, the parts of the main zones which are directly between holes or depressions stretch out, forming strands interconnecting bars which comprise the remainder of the main zones and also the intermediate zones. In order to obtain biaxial orientation, the structure must be stretched in the direction at right angles, as set out in GB No. 2 035 191A.
U.S. Pat. No. 3,906,073, U.S. Pat. No. 3,719,540 and U.S. Pat. No. 3,500,627 disclose products which apparently have main, orientated strands with the orientation therein extending from end to end. In each case, the main strands are interconnected at a plurality of positions spaced along the main strands by orientated fibrils which, at least in the case of the first two U.S. Specifications, branch out from the main strands at a small angle.